广东沿海新构造运动的大陆动力学背景

广东沿海新构造运动的大陆动力学背景了受周边板块运动影响外，还受该区大地构造演化的历史和壳幔深部结构制约。该区新构造应力场变化为：晚第三纪，陆缘裂陷盆地区为SSE为拉张，粤东、粤中沿海陆地局部为近SN向挤压；上新世晚期至今，为NWW-SEE向挤压。燕山晚期以来沿海地区“华夏山系”的造山后拉伸塌陷和岩石圈拆沉作用，导致地壳张裂，软流圈上涌，对广东沿海的新构造运动重要的控制作用。此外，广东沿海上地幔的高热状态和地壳内部的流变分层结构，是该区新构造运动和地震发生的重要的深部结构因素。

The continental dynamic settings of the neotectonic movements along the coastal areas of Guangdong Province,China

The continental dynamic settings of the neotectonic movements along coastal areas of Guangdong Province were controlled not only by the plate movements, but also by the geotectonic evolutionary history and the deep crust-mantle structures in the areas. The tectonic stress fields were changed from SSE-trending extension in the continental margin rifting basins and nearly NS-trending compression in local areas along the coasts of eastern and central Guangdong during the Neogene to NWW-SEE trending compression since the later Pliocene. It was also shown by the data of igneous petrochemistry, paleaogeography and geophysics that there was a mountain system called the Cathaysian mountain system which may be 3500-4000m high and about 500 km wide located in the southeastern China continent margin during the period of the Yanshan movements. At least in the Paleocene, the landform in southeastern China was higher than that in southwestern China. The tremendous changes of relief that may be caused by post-orogenic extensional collapse and lower lithospheric delamination, which led to the crust extension and the asthenosphere upheaval, had an important effect on the neotectonic movements along the costal areas of Guangdong. There exist lower-velocity and high-conductive layers or plastic weak layers within the crust. It was shown that the sandwich-like crust system was subjected to lateral compression, stress in the brittle layers over plastic layer would be increased because the plastic layer would transmit the force to the brittle layer by means of diapiric upwarping. The high-temperature state of upper mantle and rheological stratification within the crust is a significant deep structural factor to control the neotectonic movements and the earthquake activities along the coastal areas of Guangdong Province.